The present invention relates to a lubrication apparatus and a method of applying to an advancing yarn a lubricant consisting of a plurality of components, as well as to a lubrication pump for carrying out the method.
In the production of a freshly spun multifilament yarn, it is necessary to apply to the yarn a lubricant for further processing. Having applied the lubricant to the yarn, it is possible to guide the yarn safely, without damaging individual filaments, over contact surfaces, such as, for example, yarn guides or godets. On the other hand, the lubricant application leads to a cohesion of the filaments in the yarn. Lubricants in use are liquid emulsions, which are prepared by combining several components, for example, water and oil.
U.S. Pat. No. 3,783,596 discloses, for example, a lubrication apparatus, wherein an emulsified lubricant for lubricating the yarn is kept in a supply container. The supply container connects to a feed device, which delivers the lubricant in a metered volume flow to a wetting device. The wetting device applies the lubricant to the yarn. In this apparatus, the feed device is designed and constructed as a lubrication pump. Such lubrication pumps are constructed as single pumps with only one outlet or as multiple pumps with a plurality of outlets. Each pump outlet connects to a connection line leading to a wetting device. The lubrication pump receives an emulsified lubricant via a pump inlet.
However, such emulsified lubricants have only a limited shelf life, since bacteria start to grow as the storage time increases. The bacteria lead to gassing, which becomes noticeable in the form of bubbles. These gas inclusions in the lubricant cause a faulty application to the yarn in the wetting device, so that the yarn exhibits lubricant gaps, which result in filament breaks. In addition, it is necessary to clean the entire lubrication apparatus at regular intervals. A further disadvantage of the known lubrication apparatus lies in that a change of the mixing ratio of the lubricant components is possible only after the residual quantity has been used up or removed.
The known lubrication pumps deliver the emulsified lubricant in a metered quantity at a predetermined mixing ratio. In this instance, it is likewise disadvantageous that a change in the mixing ratio of the lubricant components requires consumption of the supply quantity and cleaning of the lubrication pump.
It is therefore the object of the present invention to further develop a yarn lubrication apparatus and a method of the initially described kind such that the emulsified lubricant is unable to undergo averaging.
A further object of the present invention is to provide a flexible lubrication pump, which enables a change in the mixing ratio of the lubricant components in a simple manner.
The above and other objects and advantages of the invention are achieved by the provision of a method of applying to an advancing yarn a lubricant having at least a first component and a second component, the provision of a lubrication apparatus for applying to an advancing yarn a lubricant having at least a first component and a second component, and the provision of a lubrication pump for metering and delivering a lubricant.
In accordance with one aspect of the invention, the method includes advancing separate components of a lubricant in separate feeder flows, combining the feeder flows to form a main flow of the lubricant, and applying lubricant from the main flow to the yarn via a wetting device.
In accordance with another aspect of the invention, the lubricant apparatus includes at least first and second containers for respectively containing first and second components of a lubricant. The lubricant apparatus further includes at least first and second lines respectively communicatively connected to the first and second containers. The first and second components are capable of flowing respectively from the first and second containers via the first and second lines. The lubricant apparatus further includes a feed device having an outlet. The feed device is communicatively connected to both the first and second lines so that the feed device is capable of receiving the first component from the first line and the second component from the second line. The feed device is operative for combining the first component received from the first line with the second component received from the second line to form the lubricant. The feed device is also operative for supplying a main flow of the lubricant at the outlet of the feed device. The lubricant apparatus further includes a wetting device communicatively connected to the outlet of the feed device and thereby capable of receiving the main flow of the lubricant from the outlet of the feed device. The wetting device is operable for applying the lubricant from the main flow to the yarn.
The invention offers the special advantage that the components of the lubricant are combined with one another only directly before applying the lubricant to the yarn. The emulsion develops a short time before it is applied to the yarn. To this end, the components of the lubricant are kept in the separate containers. Each of the containers connects via a separate line to the feed device, which has an inlet channel for each line. Within the feed device, the separate feeder flows carrying the components are combined to form the main flow. Thus, the components of the lubricant are mixed together only in the main flow, and subsequently delivered to the wetting device for lubricating the yarn.
To be able to adjust and maintain a certain mixing ratio between the components, one component is supplied in a metered quantity to a further component and mixed therewith according to an advantageous further development of the invention. In particular in the case that only a very small quantity of a component needs to be added to a basic component, it is possible to adjust the predetermined mixing ratio safely by metering the component of a small quantity.
In a particularly advantageous further development, each feeder flow is associated to a separate metering means. These metering means are controllable independently of one another. As a result, it is possible to adjust and maintain a predetermined mixing ratio of a very high accuracy and constant quality. By changing the individual metered quantities at the metering means, it is possible to change the mixing ratio of the components in a simple manner. The metering means may be constructed, for example, as metering valves which are arranged in the lines between the supply container and the feed device.
To make it possible to construct the lubrication apparatus of the present invention as compact as possible, it is proposed to associate a separate metering means to each inlet channel of the feed device.
Especially advantageous is a variant of the invention in which the metering means are formed each by a controllable metering pump. Thus, the feed device assumes the function of conveying and metering at the same time. A further advantage lies in that the lubricant is delivered to the wetting device in a predetermined metered quantity. The metered quantity that is to be maintained for application to the yarn is composed of the sum of individual metered quantities of the feeder flows.
To obtain an as intensive mixing of the components as possible, the main flow advances through a mixing chamber. Advantageously, in the mixing chamber one or more mixing means are arranged, so that the components of the lubricant can be uniformly mixed together. However, it is also possible to use as a mixing means a dynamic mixer. To this end, use is made of rotating mixing means for mixing the components in the mixing chamber.
For applying the lubricant to the advancing yarn, the lubrication apparatus of the present invention possesses a wetting device. Such wetting devices may be designed and constructed, for example, as a lubrication stick, a lubrication nozzle, or a lubrication roll. In this connection, in particular the stick lubrication and nozzle lubrication will require a metering of the main flow, which is advantageously obtained from individually metering the components.
In accordance with another aspect of the invention, a lubrication pump includes at least one pump inlet and at least one pump outlet, and conveying means communicatively connecting the pump inlet and the pump outlet. The conveying means is responsive to being driven for delivering in a metered volume flow from the pump inlet to the pump outlet. The pump further includes a mixing chamber communicatively connected to and upstream from the pump inlet. The mixing chamber includes a plurality of inlet openings and a plurality of mixing elements. The mixing elements are positioned in the mixing chamber, downstream from the inlet openings, and upstream from the pump inlet.
The lubrication pump of the present invention has the advantage that the components of the lubricant are combined and mixed only within the lubrication pump. Thus, the emulsion develops in the mixing chamber of the lubrication pump a short time before being applied to the yarn. To this end, the lubrication pump includes the plurality of inlet openings to the mixing chamber. In the inlet openings, the separate components are introduced unmetered or metered into the mixing chamber. In the mixing chamber, the plurality of mixing elements are arranged between the inlet openings and the actual pump inlet to provide an intensive mixing of the components. A lubricant combined at a predetermined mixing ratio is thus present at the pump inlet, and delivered by the conveying means of the lubrication pump in a metered volume flow to the pump outlet.
Thus, the lubrication pump of the present invention makes it unnecessary to keep a supply of an emulsified lubricant. As a result, it is possible to change the lubricant as well as vary its concentration in a simple manner. Also, the lubrication pump of the present invention makes it unnecessary to clean the lubricant supply lines to the lubrication pump in the case of a lubricant change or because of bacteria growth in the lubricant, since the feed lines connect to the mixing chamber and the feed lines convey separate components of the lubricant.
In a particularly advantageous further development of the lubrication pump, the mixing elements are mounted at least in part to a mixing shaft extending into the mixing chamber. The mixing shaft is rotatably driven, so that the components of the lubricant undergo an intensive and uniform mixing.
In a particularly preferred variant of the lubrication pump according to the invention, the mixing shaft and the conveying means are driven by a common drive. This permits influencing both the metering and the mixing by a drive control system. In this variant, it will be especially of advantage when the conveying means can be driven by a drive shaft which extends with its one end into the mixing chamber and forms the mixing shaft. To this end, it will be necessary to arrange the mixing chamber and the conveying means in alignment with each other. This results in a particularly compact type of construction of the lubrication pump.
To realize in the mixing chamber an intensive mixing of the lubricant components irrespective of the rotational speed of the conveying means and, thus, irrespective of the metered volume flow, another development of the invention is especially advantageous. In this instance, the drive shaft and the mixing shaft are interconnected by a transmission gearing. Thus, while a common drive remains, it is possible to operate the mixing shaft at substantially different rotational speeds. It is preferred to drive the mixing shaft at higher rotational speeds.
To obtain a uniform, little pulsating volume flow, which can be metered with a high accuracy, the conveying means of the lubrication pump is formed preferably by one or even more paired gears. With the use of a multiple pump with several pairs of gears, each pair of gears is associated with its own pump outlet. The supply to the paired gears is proceeded by a central pump inlet. In such multiple gear pumps, the drive gears are driven together via a drive shaft.
The lubrication pump of the present invention is suitable to supply any desired wetting device, such as, for example, lubrication sticks, lubrication nozzles, or even lubrication rolls.